The vagus nerve stimulator (VNS) is a therapy used to treat seizures. This technique relies on a pacemaker-like device that is implanted under the skin of the chest and supplies intermittent electrical impulses to the vagus nerve as it passes through the neck. The vagus nerve is a cranial nerve within the autonomic nervous system that influences motor functions in the larynx, diaphragm, stomach, and heart. Intermittent stimulation of this nerve with low-intensity electrical impulses may reduce seizures in some people. This therapy is most often used in conjunction with medications.